| Message ID | 68925276.69ZJuSpAmI@positron.chronox.de (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
On Thu, Jan 18, 2018 at 08:41:09PM +0100, Stephan Müller wrote: > Hi Herbert, > > Sorry, I forgot to CC you on this patch -- v2 is unchanged from the > original patch. It only adds you in copy. > > ---8<--- > > GCM can be invoked with a zero destination buffer. This is possible if > the AAD and the ciphertext have zero lengths and only the tag exists in > the source buffer (i.e. a source buffer cannot be zero). In this case, > the GCM cipher only performs the authentication and no decryption > operation. > > When the destination buffer has zero length, it is possible that no page > is mapped to the SG pointing to the destination. In this case, > sg_page(req->dst) is an invalid access. Therefore, page accesses should > only be allowed if the req->dst->length is non-zero which is the > indicator that a page must exist. > > This fixes a crash that can be triggered by user space via AF_ALG. > > CC: <stable@vger.kernel.org> > Signed-off-by: Stephan Mueller <smueller@chronox.de> Patch applied. Thanks.
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c index a5ee78d723cd..34cf1c1f8c98 100644 --- a/arch/x86/crypto/aesni-intel_glue.c +++ b/arch/x86/crypto/aesni-intel_glue.c @@ -824,7 +824,7 @@ static int gcmaes_decrypt(struct aead_request *req, unsigned int assoclen, if (sg_is_last(req->src) && (!PageHighMem(sg_page(req->src)) || req->src->offset + req->src->length <= PAGE_SIZE) && - sg_is_last(req->dst) && + sg_is_last(req->dst) && req->dst->length && (!PageHighMem(sg_page(req->dst)) || req->dst->offset + req->dst->length <= PAGE_SIZE)) { one_entry_in_sg = 1;
Hi Herbert, Sorry, I forgot to CC you on this patch -- v2 is unchanged from the original patch. It only adds you in copy. ---8<--- GCM can be invoked with a zero destination buffer. This is possible if the AAD and the ciphertext have zero lengths and only the tag exists in the source buffer (i.e. a source buffer cannot be zero). In this case, the GCM cipher only performs the authentication and no decryption operation. When the destination buffer has zero length, it is possible that no page is mapped to the SG pointing to the destination. In this case, sg_page(req->dst) is an invalid access. Therefore, page accesses should only be allowed if the req->dst->length is non-zero which is the indicator that a page must exist. This fixes a crash that can be triggered by user space via AF_ALG. CC: <stable@vger.kernel.org> Signed-off-by: Stephan Mueller <smueller@chronox.de> --- arch/x86/crypto/aesni-intel_glue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)